Solve the system of equations by the addition method. -2x+y= -5 8x-4y = 20 Select the correct choice below and, if necessary, fill in the answer box to complete your choice. OA. The solution is (Simplify your answer. Type an ordered pair.) OB. There are infinitely many solutions; {(x,y)| -2x+y=-5} or {(x,y) | 8x-4y=20}. OC. There is no solution; or 0.